Hi Methee Sriprapun,

There is no difference in results in ELISA results between plasma and serum. I have used both.

Roopesh

Dear Methee

Your question is a simple question with two opposite answers. There is no difference between two samples, there are a significant difference between two samples results.

It means there is no general rule such as below:

Rule 1: All assay results are the same for serum and plasma (It is wrong).

Rule 2: All assay results are higher in serum than plasma (It is wrong).

Rule 3: All assay results are higher in plasma than serum (It is wrong).

It is not only dependent to analyte, to anticoagulant, but also depend to the method.

It means, it may be serum and plasma results in a method be the same and the results in a second method be different.

It may be the results of serum and EDTA-plasma be the same, but between serum and heparin-plasma be different and visa versa.

e.g. The concentration differences in results for analytes such as: calcium, glucose, inorganic phosphorus, and total protein between serum and heparinized plasma are to be large enough to affect clinical interpretation in certain instances. But for potassium both sample acceptable.

Note: For potassium serum and plasma, both acceptable in Flame Photometer assay, but not in enzymatic method.

Finally, there is no general rule and unique answer for your question, and it depends on: Analyte, anticoagulant and method at least. You have to check the suitable sample for each analyte and each method. For many cytokines, such as IL-6, TNF-a, IL-1beta, using ELISA method, most producers and most published papers, consider serum and plasma as the same suitable samples.

Best

Mehdi

does fluoride interfere with ELISA?

Sodium azide is an inhibitor of HRP. I do not know about fluoride!!

Simple answer: Plasma is much more native. The coagulation taking plasce in serum runs via a lot of serine-proteases. They are still active, even if the serum is fully coagulated. This proteases are anything but specific. Sure the coagulation factors will be activated in the right way with a high reaction speed so that the coagulation starts after 20 sec and is ready after about 20 min. The difference in the clevage of other proteins (and cytokine are highly sensitive for an inactivation by serine proteases) is the reaction speed only. So storage, time to freezing, temperature, thawing time & temp. etc. will play an important role. 

In the lab med, most of us prefer plasma but serum is much more traditional. Have a look at your test description. most of the suppliers describes for what kins of samples the assay con be used fore. 

Has anyone done an ELISA with liver homogenates? I am looking for articles and other resources to help me determine if I should use plasma or liver homogenates for my analysis. One manufacturer has a note explaining that some tissues such as liver, kidney, and brain tissue may cause false positive results, as endogenous biotin will interact with avidin and streptavidin. I am wondering if this has been the case for anyone else?

Thank you,

Erin

Dear Erin Smith,

Heparinized Plasma is preferred , but if you want to use liver homogenates you will have to follow the instructions for the separation of your desired protein from the liver homgenate first and then go for ELISA......